Optimization of pump-valve combined regulation strategy for electric pump-fed system in a hybrid rocket motor

Advanced technology of motors and batteries has stimulated the application of the emerging electric pump in the propulsion systems. Hybrid rocket motor, characterized by the simplified thrust variation, substantially augment spacecraft manoeuvrability. The thrust adjustment capability of the hybrid rocket motor can be further improved by adopting the electric pump-fed system which features rapid and significant regulating ability. This paper details the design of a hydrogen peroxide electric pump-fed system for variable thrust hybrid rocket motor. However, the system has a wide variation in parameters and confronts unsteady dynamic processes. When parameters change rapidly and significantly, multiple systems exhibit stiffness, and the solutions present strong instability. Therefore, mastering precise dynamic simulation and achieving efficient and stable wide-range regulation represents a key challenge. In this research, simulation models of the basic components and overall hydrogen peroxide electric pump-fed system were established. Based on the modular method, the supply system is dissected into its foundational elements—namely pipelines, tanks, electric pumps, and valves. The lumped parameter method and the distributed parameter method are employed to address the issue of different time scales in the various component models. Meanwhile, the cold flow test was conducted. Through the comparison of the test and simulation results, it can be concluded that the error of the pump pressure, pump speed and oxidizer flow rate is less than 2%, which can verify the accuracy of the simulation model. Based on the high-precision models involving multiple components, disciplines, and physics, this paper explores the optimal combined regulation strategy of pump speed and valve opening during start-up and wide-range thrust variation process. The results demonstrate that through the implementation of a Multi-Layer Perceptron-based optimized strategy, the energy consumption and current pulse of the wide-range thrust variation process are reduced by 22 % and 90 %, respectively, contrasted with the traditional linear adjustment method, which improves the efficiency and safety of the system. This research provides valuable guidance for the design of the electric pump-fed system and fosters the development of advanced hybrid propulsion technologies.